Ophthalmic Lens Material Research Articles

Ophthalmic Hydrogel Contact Lens Material Containing Magnesium Oxide Nanoparticles and 3-(Trifluoromethyl)styrene for Biomedical Application.

This research was conducted for the synthesis and application of ophthalmic lens materials with improved oxygen permeability and durability. Polyvinylpyrrolidone (PVP), N-vinyl-2-pyrrolidone (NVP), 3-(trifluoromethyl)styrene (3-TFMSt), and magnesium oxide nanoparticles were used as additives for the basic combination of 2-hydroxyethyl methacrylate (HEMA). Additionally, the materials were copolymerized with ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent and azobisisobutyronitrile (AIBN) as the initiator. The addition of magnesium oxide nanoparticles was found to increase the tensile strength from 0.0631 to 0.0842 kgf/mm2. Copolymerization with a small amount of 3-TFMSt of about 1% increased the tensile strength to 0.1506 kgf/mm2 and the oxygen permeability from 6.00 to 9.64 (cm2/s)∙(mLO2/mL·mmHg)∙10-11. The contact lens material produced using N-vinyl-2-pyrrolidone and magnesium oxide nanoparticles as additives satisfied the basic physical properties required for hydrogel contact lenses and is expected to be used usefully as a material for fabricating high-performance hydrogel lenses.

Poly (Ethylene Glycol) Methyl Ether Methacrylate-Based Hydrogel and Cerium(IV) Oxide Nanoparticles as Ophthalmic Lens Material.

The functional hydrogel lens containing 2-hydroxyethylmethacrylate (HEMA) was manufactured by thermal polymerization. The physical properties of the produced hydrogel lens were measured and analyzed. In this study, HEMA, ethylene glycol dimethacrylate (EGDMA), and azobisisobutyronitrile (AIBN) were used for thermal copolymerization. Additionally, poly (ethylene glycol) methyl ether methacrylate (PEGMEMA), 3-(Triethoxysilyl) propyl isocyanate (TEPI), and cerium(Ⅳ) oxide nanoparticles were used as additives to make a functional hydrogel lens. The mixture was heated at 100 °C for 90 min to produce the hydrogel ophthalmic lens by the cast mold method. The resulting physical properties showed that the water content and refractive index of the sample were in the ranges of 38.06~42.11% and 1.426~1.436, respectively. The addition of cerium oxide nanoparticles lowered the contact angle and allowed the hydrogel lens to block UV light. The tensile strength was also improved by 52.13% through cerium oxide nanoparticles, and up to 123.4% by using TEPI. Based on the results of this study, the produced ophthalmic lens is suitable for durable, UV-blocking high-performance lenses.

Preparation and Analysis of Functional Silicone Hydrogel Lenses Containing ZrO₂ and Antimony Tin Oxide Nanoparticles.

This study prepared silicone hydrogel ophthalmic lenses using 2-hydroxyethylmethacrylate (HEMA), synthesized silicone monomer (SID), dimethylarsinic acid (DMA), N-hydroxyethyl acrylamide (HEA), ethylene glycol dimethacrylate (a crosslinking agent, EGDMA), and azobisisobutyronitrile (an initiator, AIBN). Also, Zirconium oxide (ZrO₂), antimony tin oxide (ATO) nanoparticles were added to the silicone hydrogel material to analyze the characteristics of the nanoparticles. The mixture was heated at 130 °C for 2 hours to produce the ophthalmic contact lens by cast mould method. As a result, the manufactured silicone hydrogel lens was prepared having high oxygen permeability and tensile strength while satisfying the basic requirements of ophthalmic hydrogel lens materials. Also, the addition of ZrO₂ NPs increased tensile strength of the manufactured lens, and ATO NPs were found to improve wettability. Therefore, ZrO₂ and ATO nanoparticles can be used effectively as additives for functional ophthalmic silicone hydrogel lenses.

Study on Dispersant and Surface Analysis of Ophthalmic Lens Materials Containing Carbon Nanotubes.

In this study, two types of carbon nanotubes were used as ophthalmic material, and hydrogel contact lenses were polymerized by adding two types of dispersants to effectively exert the functions of carbon nanotubes. The physical properties and surfaces of the ophthalmic hydrogel lenses prepared to confirm the functionality as a dispersant were compared and analyzed to find the utility as an ophthalmic lens material. For the polymerization, single-walled carbon nanotubes (SWCNTs), single-walled carbon nanotubes carboxylic acid functionalized (SWCCNTs), 2-hydroxyethyl methacrylate (HEMA), ethylene glycol dimethacrylate (EGDMA, a crosslinking agent), and azobisisobutyronitrile (AIBN, an initiator) was used. In addition, as a dispersant, PVP (polyvinylpyrrolidone) and BYK-111 were copolymerized. As a result of this study, PVP increased the water content and decreased refractive index regardless of the type of carbon, whereas BYK-111 did not show a significant difference in basic properties. Also, PVP gradually decreased breaking strength, while BYK-111 gradually increased breaking strength. BYK-111 effectively exerted the function of carbon nanotubes, and it was confirmed whether it was dispersed through TEM. Therefore, if carbon nanotubes are used as ophthalmic materials by utilizing BYK-111, it considered to be used as functional ophthalmic lens materials.

Copolymerization of Acrylic Monomers and Silane Group Containing Titanium Carbide Nanoparticles for Application to Ophthalmic Lens Materials.

This research was conducted to synthesis and application for high oxygen permeable ophthalmic lens materials. 2-(Trimethylsiloxy)ethyl methacrylate (2T), 3-[Tris(trimethylsiloxy)silyl]propyl methacrylate (3T), [(1,1-Dimethyl-2-propynyl)oxy]trimethylsilane (TMS), Poly(ethylene glycol) methyl ether methacrylate (PEGMA), N-vinyl-2-pyrrolidone (NVP) and titanium carbide nanoparticles were used as additives for the basic combination of synthesized silicone monomer (SiD) and N,N-Dimethylacetamide (DMA). And also, the materials were copolymerized with ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent, azobisisobutyronitrile (AIBN) as the initiator. The copolymerization with a small amount of silane of about 1% increased the oxygen permeability to 30.3˜33.52(cm²/sec)·(mlO₂/ml·mm Hg)·10-11, and in particular, the addition of titanium carbide nanoparticles was found to increase to 46.38 (cm²/sec)·(ml O₂/ml·mm Hg)·10-11. Surface modification was possible with various wetting agents. Especially, simultaneous use with titanium carbide nanoparticles increased the wettability while maintaining water content. These materials are considered to make synergy effect each other, so it can be used in functional hydrogel ophthalmic lenses.

Fundamentals of ophthalmic dispensing – part 9: Properties of lens materials

Tina Arbon Black takes a look at the optical, physical and mechanical properties of ophthalmic lens materials

Utilization of TBDMS chitosan for synthesis of photoactive chitosan derivatives and application in photografting on ophthalmic lens material

Three photoactive chitosan derivatives were synthesized using TBDMS chitosan as the starting material. In this study, we also report an optimized method for producing relatively high average molecular weight chitosan precursors for the synthesis of the three N-modified chitosan derivatives having a N-azidobenzoyl group, a N-methacryloyl group and a N-azidobenzoyl-N′,N′,N′-(acetyl-trimethyl ammoniumyl) group. The methacryloyl and azidobenzoyl derivatives synthesized were photografted onto discs of a crosslinked polymethacrylate copolymer used in the industrial production of intraocular lenses (IOLs), with dimensions comparable to those of IOLs. The photografted polymethacrylate was loaded with the antibiotic moxifloxacin, allowing the creation of an antibiotic releasing system that may be further developed for an application in postoperative endophthalmitis prophylaxis.

Polymerization and Preparation of High Functional Ophthalmic Lens Material Containing 2-Fluoro Styrene with Si and Ag Nanoparticles

This research was conducted to produce the high functional silicone hydrogel ophthalmic lens containing styrene group and nanoparticles. 2F (2-fluorostyrene) was added to enhance polymerization stability during lens formation, Si and Ag nanoparticles were used as additives for the basic combination including Sil-H (Silicone monomer), TSMA (Trimethylsilyl methacrylate), DMA (N,N-Dimethylacetamide) and MMA (methyl methacrylate). And also, the materials were copolymerized with EGDMA (ethylene glycol dimethacrylate) as the crosslinking agent and AIBN (azobisisobutyronitrile) as the initiator. Measurement of the physical, optical, surface and antimicrobial characteristics of the produced material showed the possibility of utilization as an opthalmic contact lens. As a result of the polymerization stability measurement, no significant difference was observed in all the samples, so it can be judged that the stabilization of nanoparticles in the polymer was maintained. Therefore, these materials are expected to satisfy the basic requirements of ophthalmic lenses and used usefully as an antimicrobial material for silicone hydrogel ophthalmic lens.

Preparation and Performance Analysis of Ophthalmic Polymer Using SWCNT and SWCCNT

The purpose of this study is to fabricate an ophthalmic lens by copolymerizing two types of carbon nanotubes and hydrophilic hydrogel lens materials, and to investigate its application as an ophthalmic lens material by analyzing its physical properties and antimicrobial effect. For polymerization, HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate), a crosslinking agent, and AIBN (azobisisobutyronitrile), an initiator, are used as a basic combination, and a single-walled carbon nanotube and a single-walled, carboxylic-acid-functionalized carbon nanotube are used as additives. To analyze the physical properties, the water content, refractive index, breaking strength, and antimicrobial effect of the fabricated lenses are measured. The fabricated lenses satisfies all the basic properties of the basic hydrogel ophthalmic lens. The water content increases with increasing amount of additive and decreases with addition of 0.2% ratio of nanoparticles. The refractive index is inversely proportional to the water content result. As a result of the antimicrobial test of the fabricated lens, the addition of carbon nanotubes shows an excellent antimicrobial effect. Therefore, it is considered that the fabricated lens can be applied as a functional material for basic ophthalmic hydrogel lenses.

Preparation and Characterization of High Functional Ophthalmic Lens Material Containing Acrylic Formation Isocyanate Group with Carbon Nanoparticles.

This research was conducted to produce the high functional hydrogel ophthalmic lens containing iso-cyanate group and nanoparticles. IsoMA (2-Isocyanatoethyl methacrylate) and carbon nanoparticles were used as additives for the basic combination including HEMA (2-hydroxyethyl methacrylate), MA (methacrylic acid), and MMA (methyl methacrylate). And also, the materials were copolymerized with EGDMA (ethylene glycol dimethacrylate) as the cross-linking agent and AIBN (azobisisobutyronitrile) as the initiator. Measurement of the physical characteristics of the produced material showed that the refractive index was 1.4027~1.4446, water content 31.13~44.01%, contact angle 43.99~65.67°, visible light transmittance 26.17~92.13%, and tensile strength 0.0652~0.2528 kgf. The breaking strength were in the range of 0.0872~0.1851 kgf. These results showed the decrease of contact angle and increase of water content by the addition of IsoMA and carbon nanoparticles and that showing both additives made synergy effect of wettability. As a result of the absorbance measurement, no significant difference was observed in all the samples, so it can be judged that the stabilization of nanoparticles in the polymer was maintained. Therefore, these materials considered to satisfy the basic requirements of ophthalmic lenses with high performance of tensile strength, breaking strength and wettability.

Preparation and Characterization of Functional Ophthalmic Polymer Containing Nanoparticles Using Heat Treatment Method After Polymerization

The functional hydrogel lens containing HEMA (2-hydroxyethylmethacrylate) was manufactured by thermal polymerization and heat treatment method after room temperature polymerization, respectively. In this study, HEMA, EGDMA (ethylene glycol dimethacrylate) and the initiator AIBN (azobisisobutyronitrile) were used for thermal copolymerization and the mixture was heated at 100 °C for 1 hour. And also, HEMA, EGDMA, the initiator and distilled water were used for heat treatment method after room temperature copolymerization and the mixture was heated 80 °C for 1 hour and then treated at 100 °C for 1 hour to produce the hydrogel ophthalmic lens by cast mold method. To make the functional hydrogel lens, ZnPC and platinum octaethyl porphyrin were used as additives. The measurements of the physical characteristics of the copolymerized material showed that refractive index and contact angle of sample was in the range of 1.4010∼1.4585 and 21.46∼87.28°, respectively. In case of heat treatment method after room temperature copolymerization, the refractive index and wettability of sample was higher than that of thermal polymerization. And also, the addition of ZnPC nanoparticles allowed the hydrogel lens to block UV-light. The absorbance value of solution in which the lens prepared by the heat treatment method was immersed were much lower than that of thermal polymerization, so it can be judged that the stabilization of produced polymer maintained well. Based on the results of this study, the produced optical lens can be considered to satisfy the basic requirements of optical lens and can be used effectively as an additive for functional ophthalmic lens material with high refractive index and wettability.

Fabrication and Processing Method of Ophthalmic Hydrogel Tinted Lens Containing Indium Tin Oxide-Composited Materials

In this study, a multifunctional ophthalmic lens material with an electromagnetic shielding effect, high oxygen permeability, and high water content is tested, and its applicability is evaluated. Metal oxide nanoparticles are applied to the ophthalmic lens material for vision correction to shield harmful electromagnetic waves; the pyridine group is used to improve the antibacterial effect; and silicone substituted with urethane and acrylate is employed to increase the oxygen permeability and water content. In addition, multifunctional tinted ophthalmic lens materials are studied using lens materials with an excellent antibacterial effect (2,6-difluoropyridine, 2-fluoro-4-pyridinecarboxylic acid) and functional (UV protection, high wettability) lens materials (2,4-dihydroxy benzophenone, 2-hydroxy-4-(methacryloyloxy)benzophenone). To solve problems such as air bubbles generated during the polymerization process for the manufacturing and turbidity of the lens surface, polymerization conditions in which the defect rate is minimized are determined. The results show that the polymerization temperature and time are most appropriate when they are 110 oC and 40 minutes, respectively. The optimum injection amount of the polymerization solution is 350 ms. The turbid phenomenon that appears in lens processing is improved by 10 to 95% according to the test time and conditions.

Improving sustained drug delivery from ophthalmic lens materials through the control of temperature and time of loading

Although the possibility of using drug-loaded ophthalmic lens to promote sustained drug release has been thoroughly pursued, there are still problems to be solved associated to the different alternatives. In this work, we went back to the traditional method of drug loading by soaking in the drug solution and tried to optimize the release profiles by changing the temperature and the time of loading. Two materials commercially available under the names of CI26Y and Definitive 50 were chosen. CI26Y is used for intraocular lenses (IOLs) and Definitive 50 for soft contact lenses (SCLs). Three drugs were tested: an antibiotic, moxifloxacin, and two anti-inflammatories, diclofenac and ketorolac. Sustained drug release from CI26Y disks for, at least 15 days, was obtained for moxifloxacin and diclofenac increasing the loading temperature up to 60 °C or extending the loading time till two months. The sustained release of ketorolac was limited to about 8 days. In contrast, drug release from Definitive 50 disks could not be improved by changing the loading conditions. An attempt to interpret the impact of the loading conditions on the drug release behavior was done using solid-state NMR and differential scanning calorimetry. These studies suggested the establishment of reversible, endothermic interactions between CI26Y and the drugs, moxifloxacin and diclofenac. The loading temperature had a slight effect on the mechanical and optical properties of drug loaded CI26Y samples, which still kept adequate properties to be used as IOL materials. The in vivo efficacy of CI26Y samples, drug loaded at 60 °C for two weeks, was predicted using a simplified mathematical model to estimate the drug concentration in the aqueous humor. The estimated concentrations were found to comply with the therapeutic needs, at least, for moxifloxacin and diclofenac.

Preparation and Characterization of Ophthalmic Lens Materials Containing Titanium Silicon Oxide and Silver Nanoparticles.

Hydrogel ophthalmic lenses containing fluorine-substituted aniline group, titanium silicon oxide nartoparticles, and silver nanoparticles were copolymerized, and the physical and optical properties of the hydrogel lenses were measured. To produce the hydrophilic ophthalmic lenses, the additives were added to the mixture containing HEMA, NVP, MA, EGDMA, and AIBN. The cast mold method was used for the manufacture of the hydrogel ophthalmic lenses, and the produced lenses were completely soaked in a 0.9% NaCl normal saline solution for 24 hours for hydration. The physical properties of the produced macromolecule showed that the water content was 32.5-37.6%, the refractive index was 1.450-1.464, the UV-B transmittance was 0.5-35.2%, and the contact angle was between 56 and 69°. Also, the addition of aniline, titanium silicon oxide, and silver nanoparticles allowed the ophthalmic lenses to block UV. These results show that the produced macromolecule can be used as hydrophilic lenses for ophthalmologic purposes that can block UV.

Physical Properties of Ophthalmic Copolymers Containing Vinylaniline and ZnO Nanoparticles

The mixture of vinylaniline and 2-hydroxyethyl mrthacrylate mixed according to the mixing ratio, was allowed to stir in order to add functionality. ZnO nanoparticles, dispersed for approximately 1 hr in an ultrasonic bench top cleaner, were added to the mixture of monomers. Then the mixture at a mould was thermally polymerized to prepare high-performance hydrogel ophthalmic lens. The produced ophthalmic hydrogel lens was then put in 0.9% NaCl (normal saline solution) for 24 hrs for hydration, and various measurements were carried out. The surface analysis of ZnO nanoparticles dispersed in the macromolecular polymer was conducted using AFM (XE-100, Parks System). The produced hydrogel lens generally exhibited yellowish color, transparent and hydrophilic characteristics. Also, the contact lenses hydrated in standard saline solution generally exhibited the characteristics of flexibility and softness. The physical properties of the ophthalmic hydrogel lens material were measured. The refractive indexes of 1.359-1.423, water content of 37%-43%, and visible transmittance of 74%-82% were obtained.

Ophthalmic Application of Poly(HEMA)s Containing Nanoparticles and Dimethylacrylamide

High functional ophthalmic lens materials, poly(HEMA-co-MMA)s were prepared by the copolymerization of HEMA, MMA, MA, EDGMA, and N,N-dimethylacrylamide in the presence of platinum nanoparticles with antimicrobial properties. The hydrophilic monomer N,N-dimethylacrylamide has excellent biocompatibility and oxygen transmissibility. The combination where platinum nanoparticles were added produced a colorless transparent lens. The water contents were in the range of 36.68-44.08% and the refractive index was measured to be in the range of 1.424-1.436. Meanwhile, the oxygen transmissibility ranged from 11.13 x 10(-11) to 17.63 x 10(-11) (cm2/sec) (mlO2/ml x mm Hg) increased with increasing the addition ratio of N,N-dimethylacrylamide. The physical properties measurements of the produced polymers showed that the nanoparticles did not show significant effect on the water content and refractive index of the hydrogel contact lens, but the materials effected to reduce oxygen permeability to a certain extent. The copolymers have excellent oxygen permeability, indicating that the material can be used to fabricate hydrogel contact lenses with high oxygen transmissibility.

Optical application of poly(HEMA-co-MMA) containing silver nanoparticles and N,N-dimethylacrylamide

High functional ophthalmic lens materials, poly(HEMA-co-MMA)s, were prepared by the copolymerization of HEMA, MMA, NVP, EDGMA, and N,N-dimethylacrylamide in the presence of silver nanoparticles. Silver nanoparticles have antimicrobial properties and a hydrophilic monomer N,N-dimethylacrylamide has excellent biocompatibility and oxygen transmissibility. The water content was in the range of 36.63–44.45%, indicating the characteristics of general water-content contact lenses, and the refractive index was measured to be in the range of 1.423–1.435. Meanwhile, the oxygen transmissibility ranged from 10.63×10−11 to 18.85×10−11 (cm2/sec)(mlO2/ml×mmHg) increasing with increasing the addition ratio of N,N-dimethylacrylamide. The polymeric materials satisfied the basic characteristics required for ophthalmic contact lenses. The polymers can be used to fabricate antimicrobial hydrogel contact lenses with high oxygen transmissibility.

Vinylanisole을 포함한 고굴절률 안의료용 렌즈 재료에 관한 연구

ABSTRACT. This study used 3-vinylanisole and 4-vinylanisole with the cross-linker EGDMA (ethylene glycol dimethacrylate),HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), NVP (N-vinyl-2-pyrrolidone) and the initiator AIBN (azobisi-sobutyronitrile) for copolymerization. Measurement of the physical characteristics of the copolyme rized material showed that th erefractive index is 1.4496 - 1.4894, water content 22.93 - 35.50%, visible transmittance 88.8 - 90.8%. Also, measurements showe dthat the refractive index increased while the water content decreas ed as the ratio of 3-vinylanisole and 4-vinylanisole increas ed. And in cases of copolymer with 3-vinylanisole, 4-vinylanisole (added 15%) the results showed transmittance of 52.8 - 82.2%, 13. 2 - 26.2% respectively for UV-A and UV-B showing that they have UV-blocking effects. Based on the results of this study, the produced copolymer can be estimated to be suitable for use as ophthalmic lens material for high refractive index and UV- blockingeffects.

은 및 백금 나노 입자의 함량에 따른 안 의료용 소재의 물성 변화

항균성을 포함한 나노 입자는 높은 활용성으로 인해 다양한 분야에 적용되고 있다. 본 연구는 HEMA (2-hydroxyethylmethacrylate), NVP (N-vinyl pyrrolidone), MMA (methylmethacrylate)에 나노 은 및 백금을 첨가한 후 농도조건을 다양화 하여 <TEX>$70^{\circ}C$</TEX>에서 약 40분, <TEX>$80^{\circ}C$</TEX>에서 약 40분 마지막으로 <TEX>$100^{\circ}C$</TEX>에서 약 40분 동안의 열처리 공정을 거쳐 공중합 하였다. 사용된 나노 은과 백금 입자의 크기는 각각 10 ~ 20 nm를 나타내었다. 중합 후 생성된 고분자를 사용하여 물리적 특성을 측정한 결과, 함수율 34.29 ~ 39.00%, 굴절률 1.422 ~ 1.430을 나타내었으며, 가시광선 투과율 78.8 ~ 92.5% 그리고 인장강도 값은 0.149 ~ 0.179 Kgf을 나타내었다. 나노 은과 백금 입자를 사용한 안 의료용 렌즈 재료는 콘택트렌즈 적용에 요구되는 기본적인 물성을 만족하였다. Nanoparticle with antimicrobial property has been applied to various fields. This study added silver/platinum nanoparticles to HEMA (2-hydroxyethylmethacrylate), NVP (N-vinyl pyrrolidone) and MMA (methylmethacrylate) in various concentrations and copolymerized by heating at <TEX>$70^{\circ}C$</TEX> for 40 minutes, <TEX>$80^{\circ}C$</TEX> for 40 minutes, and finally, <TEX>$100^{\circ}C$</TEX> for 40 minutes. The particle size of used nano silver and platinum was 10 ~ 20 nm respectively. Using the polymer produced through the copolymerization process, the authors have produced a contact lens and measured the physical characteristics which showed water content of 34.29 ~ 39.00%, refractive index of 1.422 ~ 1.430, visible transmittance of 78.8 ~ 92.5% and tensile strength of 0.149 ~ 0.179 kgf. The ophthalmic lens material produced using silver/platinum nanoparticles satisfied the basic physical properties required for contact lens application.

Ophthalmic lens material prepared by unsaturated nitrile-polyfunctional methacrylate-styrenic monomer copolymerization

A resin having excellent ophthalmic lens performance was produced by radical polymerization ofa mixture of bifunctional methacrylate, such as tetraethylene glycol dimethacrylate or triethylene glycol dimethacrylate, a styrenic monomer such as styrene or α-methylstyrene, and acrylonitrile. We provide a totally balanced resin composition suitable for an ophthalmic lens, having a high refractive index, large Abbe number, high impact strength, low specific gravity, heat resistance, cutting processability, tintability, and durability.